Pneumatic hoisting apparatus.



Patented Apr 3, I900. H. A. PEDBICK. 4

PNEUMATIC {IUISTING APPARATUS.

(Application flied Apr. 24, 1899.)

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THE M "PEDRICK SPECIFICATIOX forming part of Application filed April 2To all 1107110171 11mg Be it known citizen of the delphla, new andHoisting Apparatus, of

a specification, reference NEUM ' ATES & AYER COMPANY,

PHILADELPHIA, PENN SYLVANIA', Assumes ro or smut :rmcn.

ATlC HOISTlNG APF'ARAE'US.

Letters Patent No. 646,458, Tdated April 3,1900

Serial 110.714.29l un model i the accompanying drawings,

This invention relates to pneumatic hoists piston-rod that is connectedto and a valve system that reg sion and exhaust of that l, lio'wnun A.lnnmcu a esiding at Philahave invented certaints in'Ineumatic followingis cylinder and piston with a projecting lift the load ulates theadmisthe motive fluid.

The present invention is designed to utilize tive agent; and itconcompressed air as a mo sists in admitting the 'air and thr of thecylinder valve to the opposite end equilibrium of pressure on opp thepiston, and then releasing from either side of the piston valvemechanism when oper or lowering the load.

7 -ln the accompanying part of this specification,

l have hoist embodying my invention,

Figure 1 is, a side view, part1 and Fig. 2, a similar view showin partsand operating devices in.

.30 operating positions in load.

A. is the cylinder; 1

pending piston-rod and theai-r-supply with and with both with the load;.a,

pipe communicating there ends of the cylinder A erated by a handle (1-.

O isan exhaust-pipe raisingor hook D,

atin

the piston with dodirectly to one end ough a regulating.- andmaintaining an osite sides of the pressure by suitable "it in raisingdrawings, forming illustrated a in whichy in section g the various theirrelative lowering the,

that engages pipe, and b a through a val veC, op-

leading from the valve 0, and c an auxiliary exhaust-pipe communi- 0-eating with the pipe 11 check-valve 7L, that is autoumtic .by devicesthe piston;

' through a stop-valve g pipe-l1, leadm g to the eyli ton and throughthe valv The valve 0 on the inder-above and below conneotingw incidentwith the descen the piste a communicates directly with the inletnderbeneath t-he'pise C above the piston. b i'sa-three-way lates the commudsof the cyland providcdwith a ally operated ith and operating 00-. dingmovement of all as hereinafterreferred to.'

The air supply pipe n and the exposite arm i-les'the friction-collar 5on haust pipeo, leading to the atmosphere, the

valve being adjusted, as shown in Fig. 1, to

l), and whereby is reduced an. to the load lifted 'and sufficient Whenit is desired to lower the load, the

operating-valve C is turned to the position shown in Fig. 2,which openscommunication between each end of the cylinder and closes the exhaust oto the atmosphere. The piston B is then forced downward by reason of thegreater pressure on its upper greater superficial area. iaryexhaust-pipe e is also provided, which communicates directly with theupper. end of the'cylinder and the atmosphere and is fitted with acheck-valve 71, opening in wa-rdly. This s;

and always held seatedfexceptwhen opened y the free arm f of a pivotedlever, the opr being the piston-rod shown.

attachment is to maintain balanced pressure on both sides of the pistonduring the suspension of the load, the tendency of the piston beingtosettle downwardly, due principally to leakage past the piston. from itslower side. As the piston setits rodroeks'the pivoted lever 1",connected with it,causing the newopposite end f tocontact with andautomatically raise the depending 'stems oi the auxiliary exhaust-valve72-, open the latter, and permit the pressure from above the pistontoescape, escaped to balance the pressure and load the piston thcn risesslightly and releases the connection with the auxiliary exhaust-valve h,which is instantly seated by the internal pressure. mong the'advantagesderived in the present invention are being thus maintained under forcesprevents its sudden rise or collar to The on fall at all i the.

and when sufiicient air has.

the following: The piston a balance c5- side due to its Abranch or auniL0 connected by 'a' frictioin pressure is admitted of the cylinder thepiston and exhausted alternatelyfrom the 20 Ispcctive direction, asdesired, and constantly times. The piston cannot rise until thereductionpf pressure above it equals the load to be lifted. The time inequalizing the pressure after reduction iscomparatively shortened.'lhe'area on the top of thepiston being greatest, it lowers more quicklyunder the compressor-pressure.

am aware that hydraulic hoists in which to both ends of the cylinder andan equilibrium of pressure created on opposite sides of the piston a renot new, the operation of the piston in this instance being effected byforcing water alternately from one side of the piston to the other; butI am not aware that a pneumatic hoist has heretofore existe'd'wherein anequilibrium of pressure is admitted and maintained in both ends and onthe opposite sides of upper end of the cylinder to the atmosphere andfrom the lower end of the cylinder to its upper end to operate thepiston in either remaintain the load at any position upon closing theexhaust-passage.

- Having thus fullydeseriber'l my invention, what I claim, and desire tosecure by Letters Patent, is-

l. The combination with the cylinder, piston and piston-rod of apneumatic hoist havinga motive-fluid-supply pipe communicating with oneend of the cylinder, and a branchside alternately and a relief-valveopening pipe communicating with the opposite end-of the cylinder,whereby the motive fluid is'admitted to both sides of the piston and anequilibrium of pressure established, of a valve interposed in thespective ends of-the cylinder for exhausting the fluid from the to theatmosphere and from the lower end of the cylinder to its upper end, tooperate the passage between the re-' upper end of the cylinder piston ineither direction, substantisllv s described.

2. In a inder, piston, pp p p end of the cylinder and intermediatelywith its opposite end, and an interposed controlling-valve adapted toadmit the direct pressure to both sides of the piston simultaneously,and to release the same from either substantially as described, communieation with the atmosphere and the cylinder above the piston;operated automatically and coinpneumatic hoist consisting of acylpist'on-rod and motive fluid- ,cidently with any downward movement ofthe position in which it may be piston from any held, as set forth.

In testimony whereof. I aflix iny signature in presence of twowitnesses. l

, HOWARD A. PEDRI'CK.

Witnesses:

J No. J. BENNETT, WALTER F. HENLY.

comm unieating directly with one

